Isolated attosecond pulses from ionization gating of high-harmonic emission

Abel, Mark J.; Pfeifer, Thomas; Nagel, Phillip M.; Boutu, Willem; Bell, M. Justine; Steiner, Colby P.; Neumark, Daniel M.; Leone, Stephen R.

doi:10.1016/j.chemphys.2009.09.016

Cited by 102 publications

(58 citation statements)

References 37 publications

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“…If a 1 μm pinhole was used, then the intensity of one of the XUV bursts should dominate and an isolated attosecond pulse, with one weak satellite pulse, could be selected from a multicycle generation experiment. This concept is similar to that of ionization gated phase-matching discussed in [20][21][22], but in a regime where the outer regions of the capillary generate significant XUV intensities it is necessary to remove these contributions by spatial filtering to achieve isolated attosecond pulses.…”

Section: Resultsmentioning

confidence: 99%

“…Recently it has been demonstrated that phase-matching can be extended to the water-window region harmonics using a mid-infrared driving laser [17,18]. It has also been noted that the temporal variation of phase-matching conditions is crucial in determining the output from HHG experiments [19][20][21][22], however none of this work has taken into account the spatially varying phasematching conditions found in waveguide HHG.…”

Section: Introductionmentioning

confidence: 88%

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Spatiotemporal phase-matching in capillary high-harmonic generation

et al. 2012

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We present a simple phase-matching model that takes into account the full spatiotemporal nature of capillary high-harmonic generation. Spectra predicted from the model are compared to experimental results for a number of gases and are shown to reproduce the spectral envelope of experimentally generated harmonics. The model demonstrates that an ionization-induced phase mismatch is limiting the energy of the generated harmonics in current capillary high-harmonic generation experiments. The success of this model shows that phase-matching processes play a dominant role in determining the emission from capillary high-harmonic generation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

Spatiotemporal phase-matching in capillary high-harmonic generation

et al. 2012

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“…As the appearance of a broad continuum is an indication of a possible IAP, it is very tempting to speculate this transition as a transition from an APT to IAP by controlling the intensity of few-cycle mid-IR pulses. The transition from APT to IAP at very high laser intensities has has been demonstrated previously where the mechanism was ionization gating [17,31]. In ionization gating, the field is so intense that the electron is momentarily stripped from the atomic core, thus making the electric field effectively one-cycle.…”

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confidence: 94%

“…The second approach is based on polarization gating [9][10][11], and the generalized double optical gating [12][13][14], in which the short driving pulse requirement is somewhat relaxed. While these two approaches have their origin already in the single-atom response, the third approach is based on the macroscopic propagation effects [15], which includes, ionization gating [16][17][18], phase matching [19], and ionization-driven reshaping Gaarde et al [15,20]. It has also been demonstrated recently that near-continuum spectra can be generated with two-color multicycle driving laser pulses by carefully adjusting the wavelength of the supplementary pulse [21].…”

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confidence: 99%

Generation of broad XUV continuous high harmonic spectra and isolated attosecond pulses with intense mid-infrared lasers

Trallero–Herrero

Jin

Schmidt

et al. 2011

J. Phys. B: At. Mol. Opt. Phys.

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We present experimental results showing the appearance of a near-continuum in the high-order harmonic generation (HHG) spectra of atomic and molecular species as the driving laser intensity of an infrared pulse increases. Detailed macroscopic simulations reveal that these near-continuum spectra are capable of producing IAPs in the far field if a proper spatial filter is applied. Further, our simulations show that the near-continuum spectra and the IAPs are a product of strong temporal and spatial reshaping (blue shift and defocusing) of the driving field. This offers a possibility of producing IAPs with a broad range of photon energy, including plateau harmonics, by mid-IR laser pulses even without carrier-envelope phase stabilization.It has been a decade since the first reported generation of isolated attosecond pulses (IAPs) [1] and the first full characterization of an attosecond pulse train (APT) [2], both seminal results that gave birth to the field of attosecond science [3][4][5][6][7]. While APTs can be now routinely generated based on high-order harmonic generation (HHG) in gases, production of IAPs is still a very active field of research. Common to all methods of generating IAPs is the concept of temporal gating, which is used to select a XUV burst from an APT. Current methods can be divided into three different categories. The most intuitive, but technically demanding, approach is based on XUV spectral filtering near the cutoff of the HHG spectra. This approach requires a short driving pulse (about two optical cycle) with a stabilized carrierenvelope phase. [6,8]. This approach could be called intensity gating, as it selects the harmonics emitted near the peak of the most intense half-cycle of the (short) laser pulse. The second approach is based on polarization gating [9][10][11], and the generalized double optical gating [12][13][14], in which the short driving pulse requirement is somewhat relaxed. While these two approaches have their origin already in the single-atom response, the third approach is based on the macroscopic propagation effects [15], which includes, ionization gating [16][17][18], phase matching [19], and ionization-driven reshaping Gaarde et al [15,20]. It has also been demonstrated recently that near-continuum spectra can be generated with two-color multicycle driving laser pulses by carefully adjusting the wavelength of the supplementary pulse [21].In order to produce a short IAP, XUV radiation with a broad frequency bandwidth needs to be generated. Since the HHG cutoff law is Ω cutof f ∼ I L λ 2 L , there are only two ways to extend Ω cutof f : increasing the laser intensity I L , or increasing the laser wavelength λ L . The first option is limited by ionization, which dramatically reduces HHG yield due to the depletion of neutral atoms and, more importantly, the phase mismatching due to free electrons in the medium. Using a short laser pulse does not help much, since the current technology nearly reaches the one-cycle limit already. The second option is to use lasers with a lo...

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“…Isolated attosecond pulses have demonstrated a great potential in the investigation of ultrafast electronic processes, and they can be produced by spectral selection of the few harmonics in the cutoff region, which are most in phase [4][5][6]. Several other techniques have been investigated to generate isolated and twin-pulses [7][8][9][10][11][12][13][14][15][16][17][18][19], which include spectral amplitude and phase control by means of polarization and intensity modulation of the driving pulses [7][8][9][10][11][12], the use of dispersive elements for pulse compression [13], and different other techniques [14][15][16] that have been reviewed in [18,19]. These important efforts are able or promising to produce isolated attosecond pulses by considering a particular spectral bandwidth of the harmonics spectrum.…”

Section: Introductionmentioning

confidence: 99%

Broadband Spectral Amplitude Control in High-Order Harmonic Generation

Serrat

2012

Applied Sciences

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Abstract:A technique for broadband spectral amplitude control of light pulses produced in high-order harmonic generation (HHG) is presented. It has been shown elsewhere that broadband spectral phase control in HHG is achievable using a computerized feedback loop scheme by coherently adding a filtered region of the HHG emission to the intense IR driving pulse with optimal attenuation and time delay parameters. In the present study, further computational evidence of the capabilities of this control scheme is provided by considering the spectral amplitude in a broadband region of the HHG spectrum as the control target for the production of isolated attosecond pulses. Different spectral widths and central photon energies are examined, such as a spectral width of 30 eV centered at 36 eV, well in the plateau, and a width of 20 eV centered at 60 eV in the cutoff region. An iterative procedure of the method is implemented and optimal isolated single cycle pulses at a central photon energy of 36 eV are obtained. This control scheme is a fundamental tool that can be implemented for amplitude and phase shaping of any suitable spectral region in HHG.

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Isolated attosecond pulses from ionization gating of high-harmonic emission

Cited by 102 publications

References 37 publications

Spatiotemporal phase-matching in capillary high-harmonic generation

Spatiotemporal phase-matching in capillary high-harmonic generation

Generation of broad XUV continuous high harmonic spectra and isolated attosecond pulses with intense mid-infrared lasers

Broadband Spectral Amplitude Control in High-Order Harmonic Generation

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